Stencil sheet



l line. Among other Patented Mar. 30, 1926.

UNITED STATES PATENT OFFICE.

GUY LEONARD, OI BALTIMORE, MARYLAND.

STENCIL SHEET. 7

No Drawing.

To all whom it may concern:

Be it known that I, GUY LEONARD, a subject of the King of Great Britain, residing in Baltimore, in the county of Baltimore 6 and State of Maryland, have invented certain newand useful Improvements inSten cil Sheets, of which the following is a specification.

This invention relates to stencil-sheets for 1 typewriting and other work, andits principal object is to' produce an inexpensive, pliable,strong, durable and eflicient stencilsheet economical of ink, which can be stencilled in dry condition, and is not injured by rough handling, and will yield a large number of copies.

A sheet of Yoshino or other loose-fibred paper is coated by liquid which includes a large proportion of shellac solution in methyl alcohol or other solvent. With the shellac solution there is employed a solution of aluminum stearate (a salt of stearic acid) in benzol, partly' for imparting a water-proof quality to the sheet, but mainly for combin- -ing thoroughly with the shellac and making more of a film. The aluminum stearate overcomes-the brittlenesslof the dry shellac, so that instead of'the film being likely to be shattered by the type, it is jfendered tough and elastic, and is sharp-cutting. The aluminum stearate conduces to durability of the sheet, which yields many more copies than would be possible with a sheet having only a shellac film. The aluminum stearate com bines thoroughly with the shellac, and makes more of a film on the sheet, and makes the film more elastic.

To the solution of aluminum stearate in benzol, to'whioh is added a solution of shel- 40 lac in methyl alcohol, there is also added the following in a butyl alcohol solution,

namely diethylphthalate, triacetin, acetaniv lid and triphenolphosphate. The butyl'alcohol forms a solvent for said substances. Among other suitable. solutions for the aluminum stearate are amylacetate and gasoare methyl acetone, acetone, amylacetate and denatured alcohol. The aluminum stearate may be dissolved in amylacetate or gasoline. The aforesaid preparation is heatedto about 7 0 degrees centigrade and is then cooled to about .50 degrees centigrade Then there is thoroughly mixed therewith a mixsolutions for the shellac Application flledp ecember 17, 1925. seria ud. rams.

triphenolphosphate.

The oil mixture is preferably 80 parts castor oil, 20 parts oleic acid and 20 parts neats-foot oil. a

All of the above proportions are by weight. The proportion given for each ingredient holds good for the entire coating solution, as, for example, the neats-foot oil may be equal to by weightof the shellac solution. v

'Triacetin is a glycerol fatty acid ester. By the aid of the triacetin, it is designed to improve the pliability and elasticityin the stencil-sheet; the triacetin being a plastifier. Since alcohol evaporates from the coated sheet, the weight of the various other ingredients may finally be somewhat different from that given in the foregoing formula. Triacetin and oil} are mutually soluble in alcohol or ether or acetone, or any of the common solvents for shellac. The diethylhthalate is an added softening or tempermg ingredient, which is also soluble in alcohol or the other common solvents, thus. making with the shellac, triacetm, etc., a

homogeneous dry coating upon the" evaporation of the solvent.

The proportions may scope of the invention,

be varied within the and there is permissible some-latitude of variation in the in gredients themselves, a's, for example, glycerin may be used as a'substitute softening agent; or the-softening agents may be modified by glycerin or other ingredient. a

The coating preparation can begcolored with any-dye that is soluble in alcohol, or

in a common solvent of the solution. I

The coating solution may be. prepared preferably by first dissolvin the aluminum stearate 1n benzol, then ad ing the shellac solution, then mixing the liquid triacetin,

diethylphtha'late, acetanilid, and triphenol;

phosphate in a butyl alcohol solution, and adding this mixture to the foregoing. f This preparation maygthen be heated toabout 70 degrees centigrade, and then cooled to about 50 degrees centigrade. This heat will be usually sufficient for the oil ingredients. Then the mixture of castor oil, oleic acid and neats-foot oil is thoroughly admixed with said preparation. In this bath the Yoshino paper sheets may be immersed, or the sheets may be floated upon the liquid. Excess of liquid may be removed from the sheet, and the same may be hung up to dry, whereupon it is ready for use in the typewriting machine.

The invention is not limited to the proportions given, nor to the exact ingredients named, and variations may be resorted to in carrying out the process. It is not necessary in all cases to employ the entire formula, as portions thereofmay be used within the scope of the invention.

I claim:

1. A stencil-sheet of loose-fibred paper coated with a solution of shellac, aluminum stearate, diethylphthalate, triacet-in, acetanilid, triphenolphosphate, castor oil, oelic acid and neats-foot oil. I

2. A coating bath for a stencil-sheet of loose-.fibred paper having substantially the following ingredients and proportions thereof by weight, viz: aluminum stearate 40 parts; ,benzol 8O parts; shellac solution in methyl alcohol 40 per cent, 200'parts; triacetin 50 parts; diethylphthalate 80 parts;

acetanilid 10 parts; triphenolphosphate 10 parts; butyl alcohol 80' parts; castor oil 80 parts; oleic acid 20 parts; and neats-foot oil 20 parts.

3. The process of dissolving aluminum stearate in benzol, adding a solution of shellac in methyl alcohol, mixing therewith a butyl alcoholic solution of diethylphthalate, triacetin, .acetanilid and triphenolphosphate, and incorporating with the aforesaid preparation a mixture of castor oil, oleic acid and neats-foot oil.

4. The process of dissolving aluminum stearate in benzol, adding a solution of shellac in methyl alcohol, mixing therewith a butyl alcoholic solution of diethylphthalate, triacetin, acetanilid and triphenolphosphate, heating the aforesaid preparation to about 7 0 degrees centi'grade, cooling the same to about 50 degrees centigrade, and incorporating therewith a mixture of castor oil, oleicacid and neats-foot oil.

5. A stencil-sheet of loose-fibred paper coated with shellac tempered by aluminu'm' rial.

6. A stencil-sheet of loose-fibred paper coated with shellac tempered by aluminumpaper stearate, triacetin and diethylphthalate, and

acetanilid to which is added a suitable softening or shortening ingredient.

f9. A stencil-sheet of loose-fibred paper coated with shellac tempered by aluminum stearate, triacetin and diethylphtlialate, acetanilid and triphenolphosphate incorporated with a softening or shortening agent. 10. A- stencil-sheet of loose-fibred paper coatedwith shellac tempered by aluminum stearate and triacetin, and softened by a mixture of castor oil, oleic acid and neat foot oil.

11. A stencil-sheet of loose-fibred paper coated with shellac tempered by aluminum stearate, 'triacetin, diethylphthalate and acetanilid, and softened or shortened by castor oil, oleic acid and neats-foot oil.

12. A stencil-sheet of loose-fibred paper coated with shellac tempered by aluminum stearate, triacetin, diethylphthalate and acetanilid incorporated acid and neats-foot oil.

13; An ink-proof coating bath for paper, having about 320 parts by weight of a shellac solution in alcohol and aluminum stearate solution in benzol, about 230 parts by weight of a butyl alcohol solution of triacetin, diethylphthalate, acetanilid and triphenolphosphate, and about 120 parts by weight of a preparation of castor oil, oleic acid and neats-foot oil. 9

14.The process of dissolving aluminum stearate in benzol, adding a solution of shellac in methyl alcohol, mixing therewith a butyl alcoholic solution of diethylphthalate, triacetin, acetanilid and triphenolphosphate, heating the aforesaid preparation to about '70 degrees centigrade, cooling the same to with castor oil, oleie stearate and softened by oil or fatty matered by aluminum A about 50 degrees centigrade, incorporating therewith a'mixture of castor oil, oleic acid and neats-foot oil, coating a loosefibred paper with the aforesaid coating, removing surplus coating from the paper, and drying thepaper. y

our woman; 

